1. Field of the Invention
The invention relates to a method for the chemical decontamination of metallic parts of nuclear reactor installations, in which first, an oxidative treatment with a permanganate solution is applied before dicarbonic acids are used for further treatment.
2. Description of the Prior Art
In the method known from German Patent No. 26 13 351 and U.S. Pat. No. 4,226,640, which has found acceptance in practice, an alkaline permanganate solution is used for the oxidative treatment of contaminated nuclear reactor components at a temperature of about 100.degree. C. The components are subsequently flushed with demineralized water (deionate) before continuing with a citrate-oxalate solution which is adjusted with ammonia to a pH-value of 3.5. The solution contains an inhibitor as well as ethylenediamine tetraacetic acid. The inhibitor is iron-III formate.
The known method with its individual stages and in-between rinsing operations uses high chemical concentrations and the time of treatment is quite long. Also, the known method has not been applied to primary systems of nuclear reactors which would have to be practically emptied for this purpose and would have to be filled again after the treatment.